Compressor-controlling mechanism



Nom 20, 1928. l

F. D. HOLDSWORTH COMPRESSOR CONTROLLING' MECHANISM 2 Sheets-Sheet l riginal Filed Jan. 50. 1922 @mr zeg.

Patented -Nov.` 20,

UNITED sTATEsfPATENT oFFi-CE. f

' an improved 'compressor controllin mech- FRED D. no LDsWoRTH, or c LAREMoNT, NEW HAMPSHIRE, AssIGN'R To sU'LLIvAN MACHINERY COMPANY, A'coRPoRATioN or MASSACHUSETTS. v

COMPRESSQEt-GQNTRO-LLING MECHANISVM.

Application filed January-30, 1922, Serial No. 532,681:

. .My invention-relates -to compressor controlling mechanisms, and more particularly to automatic means for controllingJ the running ofthe compressor and the loading thereof at appropriate times.

Anobject of my invention is to provide anism. Another obj ect of my invention is to provide-improved means for controlling the starting and stopping of a compressor in acf cor-dance with the demands for compressed air and improved means controlled by the starting and stopping of the compressor for controlling the loading and unloading of the compressor. A further object of my invention is to provide improved electro-pneumatic control means for theloading andyunloading of a compressor. Other objects andadvantages of my invention will hereinafter more'fully appear. v

In. the accompanying vdrawings I have shown for purposes of illustration two forms which my'invention may assume in practice.

'In these drawings,- Fig. 1 is a view mainly in elevation, but

partially in section, ,of a compressor system cont-rolmeans.

provided with one illustrative form of my improved controlling means, theelectric circuits being shown diagrammatically.

. Fig. 2 is an enlarged detail view with parts shown in section.

Fig. '3 is a detail of a portion ofthe electric Fig. 4 is a view similalto 1, 4showing a modification. l

Fig. 5 isan enlarged detail section through a portion of the latter `form my. improved controlling means.

Fig. 6 is a sectionzon the line 6-6 of Fig. 4.

In the first illustrative embodiment of my invention, i. e. that which is shown in Fig uies l to '3, inclusive, I have'shown the sam applied to a compressor 1 having a cylinder 2 in whoseLbore 3 a piston 4 is adapted to be reciprocated by means of a crank shaft 5 and to the operative connections '(not shown). The compressor discharges by way ofv a pipe 6 to a receiver l7V through valve'- mechanism 8 of any'suitable form. The admissionof air compressor cylinder takes place past inlet valves 9 of familiar construction, these valves being normally tion of pressure within the cylinder bore durv1s in.` excess held closed by springs 10 save when opened by reason ofthe reduc- Renewed July 19, 192s.

ing the suction strokes of vthe piston. For the purpose of opening the inletb valves and maintaining them open and thereby unloading the compressor vwhen desired, I provide pistons l1 reciprocable in cylinders 12- to 60 which airl may bev supplied by way of connections 13 under control of mechanism 14 hereinafter more fully described, the passages 13 ,1 being connectedto the receiver as indicated at 15 through the valve mechanism 1'4.

1s controlled by a pilot switch 24 whosev move# .i

ments lare regulated by a diaphragm 25, dia- :grammatically shown in Figure 1, the diaphragm being responsive directlyfto receiver pressure by way of a direct connection26, it being noted that when the receiver pressure of any predetermineddesired 80 amount, the pilot switch 24 will be opened, While when the pressure f alls below the de sired, limit, the pilot switch will close and thereby close the main line switch 20. The main line switch has movable therewith a supplement-al switch 27 which controls the circuit through a solenoid 28 which serves in turn to close a switch 29 shunting the first resistance 16. The switch 29 carries with it a supplemental switch 30 which closes `an op- 90 erating circuit which causes the next succeedresistance-17 to be shunted and, as eachsucvce'ssive resistance shunting switch closes, it

31 which is traversed by a lsmall opening 32.

movable in an oil cylinder 33 whereby the closing movements of the switches take placei relatively slowly, while the opening movementsI are allowed to take placesharply by reason of a check valve vcontrolled bypass Aofa lfirge 'size 34.- Anexamination of the connections illustrated will show that open- 1,10

65 4 The compressor is driven by a motor diamain line switch willcause inopening of all thefresistance ing f the stantaneous shunting switches and, accordingly, that each time that the motor is stopped, it 1s brought up to speed by the the full resistance. will be observed that by reason of the presence of the dash pot mechanisms described, a suiiicient time lapse between the closing of the main switch and the cutting out.of all resistance is provided to lpermit the motor to come up to running speed.

i 'nism 14. The details of this valve ,1,141,975, which `'the depression of -the plunger 38 tothe posi!l v .shown lherein a mechanism of the type disclosed in the `patent to one John L. Osborne, mechanism operates upon tion shown in Fi re 2 to close a connection from the receiver through the valve mechanism 39 to the connections 13 and` operates upon release of the plunger 38 upon interruption 'of the current supply tothe solenoid to "supply receiver pressure 4 ers 11 andso tounload the compressor.' It

',will be' noted from an lnspectionof Figure2 ver 3.7 in depressed position, the plunger will switch 24 and there that when the solenoid no longer holds'the'lebe raised by reason of the small unbalanced area exposed to pressure thereon, and by a spring 39f forming a part of the mechanlsm 14, thereby causing the unloading of the compressor. l The mode of operation of this form of my invention will now be readily apparent. it be assumed that the parts are in the position shown in Figurel.' It ywill be evident-that the inlet valves are being. held open and so that the compressonis unloaded. v Asreceiver pressure drops due to air consumptionfor any purpose, the diaphragm 25will close the ilot y cause closing oi). the

main switch 20 and the starting of the motor. The controller mechanism will then gradually vcut out the resistance, bringing the motor up to 'speed and, when the .last resistance is cut out, the switch 35 will close the circuit through the solenoid 36 and so cause the leverJ 37 to be moyed vtoforce down the plunger 38 and b means of t e y ving ofthe` valve mechanism 39 cause` loa v mpressor by Jcutting off the suply of air beneath the plugers 11 and exaus'tin'g the cylinders 12.' When the'eceiver -1 pressure again gets too high, the pilot switch will be opened, resultin the resistance shuntin main line switch' an in theopening of all switches as'well as the also resulting in 'the opening 'of t e circuit through. the solenoid *36 whereby the plunger 38 may rise and the 1gradual cutting out ofv beneath the plung- L struction, but isprovided in addition with a supplied thereto tto oppose lspring 59.

`49. and

-terrupt the air supply through the line valve mechanism 39 operate to admitv pressure beneaththe plungers 11 to unload the compressor.

In the form of my invention, which I have shown for purposes of illustration 1n Figures '4 to 6, it will be noted thatI-have shown a compressor 40 similar to the compressor 1in every respect save that it does not have inlet Y valve controlling unloading means, but instead is provided with unloading means of the type shown in Figure 6, it being noted that the discharge line 41 from the compressor 40 communicates with a chamber 42 which is provided with ports 43 and 44 respectively opening to chambers 45 andy 46 which in their turn respectively communicate with the atmosphere by means of aline 47, and withthe receiver by a line 48. Valves 49 and 50 respectively control the -ports 43 and 44', these valves having springs 51 and 52 cooperating respectively with them, the springs 5.2 being of relatively light strength while the spring 51 is substantiallymore powerful, serving to hold the valve 49 closed when the compressor is first started up and the receiver isvempty, and operating, aided by the fluid pressure admitted into the valve 49, as hereinafter described,

to hold the valve 49closed during the time when the airvpressure-is belowthe desired point. It will be noted that the valves 49 and 95 50 are slidable upon projections 53 and 54v which form housings for the springs 51-and 52 and that the space between the projection 53 and the valve 49 is connected by a pipe 55 to a valve mechanism 56 which controls 'the communication of the pipe with a connection 57 leading to the receiver. The valve mechanism 56 is identical with that shown in the Osborne patent mentioned inits valve consolenoid 58 which is operative when current is the action of the The spring 59 is set so that maximum desired compressor discharge pressure cannot overcome the spring 59, but so that minimum defsired compressor discharge pressure aided bythe strength of the solenoid 58 can overcome the spring 59'y and permit the supply of pressure to the inside of the valve so maintain the latter seated. I t will be noted that a similar pilot switch 24 c ontrolled by a similar diaphragm 25 is provided as in the. form of m invention shown in Figure 1 and that the e ectrical controlling mechanism is identical throughout with that shown in Figure 1 and numbered 16, etc.

From the foregoing cies will be readily apparent. When receiver l pened and 'accordingly no current will be supplied to the motor or to the solenoid 58.-

Accordingly, the valve mechanism 56 will indescription the mode if' of operation of my second illustrative spe'.

and vent the latter. Thereafter, when the receiver pressure has fallen to the disired minimum and the pilot switch 24 closes, the compressor will be started without load as air compressed by the compressor can be forced out past the valve 49 to the atmospheric vent 47. When, however, the compressor has come up to speed and the last resistance shunting switch has been closed, the solenoid 58 will be energized and with the reyceiver pressure will overcome the spring 59 f* valve 50 and supply pressure past the Valve `mechanism 56 through the pipe 55 and hold the valve 49 closed. Thereafter, the air compressed by the compressor will flow past the and into the receiver. v

It will be obvious to one skilled in the art l that my improved controlling mechanism can of my invention as defined in Y cally be adapted to use with intake type unloading mechanisms and that if desired various other modifications can be made Within the scope the appended claims. A. l

While I have in this application specilidescribedtwo forms which my invention may assume yin practice, it` will be understood that these forms of the same are shown for purposes of illustration and that -f the invention may be modified and embodied ing an in various other `forms Without departing from its spirit or the scope of the appended What I claim as new and desire to secure by Letters Patent-is: L

1. In a compressor controlling lsystem, a compressor, -electric driving means therefor, pneumatic unloading means for said compressor, controller means for said driving means, and means controlled by said control- I er means for controlling said unloading means and comprising meansconstantlybiased toward one of its positions by compressor discharge pressur 2. In a compressor controlling system, a compressor, electricdriving'means therefor, unloading means for said compressor, controller means for said driving means, and means controlled by said controller means for controlling said unloading means includelement constantly pressed longitudi- .nally by compressor discharge pressure, and means controlled by said controller means for controlling said element.- i

3. In a compressor controllingwsystem, a

compressor, electric driving means therefor,

unloading mechanism for said Hcompressor, controller` means ineans forl controlling the operation of"i said unloadin mechanism yconstantly pressed longitudinally by compressor discharge pressure, means whereby) the control of said unloading means 'is effected by pressure fluid whichfconstantly presses lsaid latter means,

and electro-magnetic means 'controlled by said controller'means for governing the reforf-said driving means,-

spouse of said unloadingl mechanism controlling means to-compressor discharge pressure.

4. In a compressor controlling system, a compressor, e ectric driving means therefor, unloading mechanism for said compressor, compressor discharge pressure responsive controller means for said driving means, means constantly acted on by compressor discharge pressure tending to move the same in one direction for controlling said unloading mechanism, means whereby the control of said unloading means is effected by a pressure fluid which constantly presses said latter means, and electro-magnetic means controlled bysaid controller means for controlling said constantly discharge pressure pressed means. f

In a compressor controlling system, a compressor, electric. drivingnieans therefor, unloading mechanism for said compressor, means constantly exposed to longitudinally acting compressor discharge pressure for respectively controlling the operation of said driving means and of said unloading mecha-I nism, and means previously stationary but ling means has brought the compressor up to speed to vary the operation of the controlling means for the unloading mechanism.

6. In a compressor controlling system, a compressor, unloading means therefor comprising a controlling element vexposed to compressor discharge pressure which tends to move it in one direction, and electro magnetic control means forvcontrolling said unloading means .including means also acting upon said element when' the compressor reaches full running speed.

7. In a'compressor controlling system, la compressor, unloading means therefor, and combined electric and .discharge pressure controlled .pilot means for controlling the operation of said unloading means to effect loading at substantially full running speed.

v 8. In a compressor. controlling system, a compreor, unloading means therefor,- and combined electric and discharge pressure controlled pilot means for controlling the operation of said unloading means to effect loading at substantially full running speed, said electrica-l control being governed by the compressor discharge pressure.

llll

9..In a compressor cont-rolling system, a

compressor having inlet valves, yfluid operated means cooperating With the latter to unload the compressor, an electric driving motor for the compressor, a cont-roller therefor,

and means controlled b said controller for controlling said unloading means including -i a valve mechanism, means associated theref' the movement of said valvemiechanism.

10. The combination with a compressor, of

controlling vmechanism therefor.A ,comprising a pilot; valve mechanism operative alternatively to supply fluidv compressed lay-said "by it-isielectro-magnetically controlled and y including means for exerting a plurality of different forces to be overcome by said elec-- Aa pilot valve mechanism'operative alternacompressor and tol vent compressor and to ventthe fluid sosupplied to effect control of said compressonsaid pilot 'valve mechanism having mechanism wheretro-magnetic controlling means, one ofl said forces being pressure posing all movement by said electro-mag- 11. The combination with a compressor, of controlling mechanism therefor comprising netic controlling mechanism.

tively to supply fluid ling means.

' l2.The combination with a co-mpressor,v of controlling mechanismtherefor compris-` ing a vpilot valve -mechanism operative alsupply luid compressed by* ternatively t'o said compressor and to vent the fluid so supsupon stopping of said ;compressor,

plied to efect control of compressor, andelectro-ma etic control means for' said pilot valve mec anism, said pilotxvalve mechanism including'asurface exposed to the presv -sure medium controlled by "said pilot' valve mechanism-for constantly exerting a -orce opposing movement by said electro-magnetic means and also includin spring mechanism having to be overcome ysaid electromagnetic means. fluid produced and op- 13. In a compressor'` controlling system, a compressonan electric motor for driving the same, a receiver, a pressure switch adapted uponlincrease in receiverpr'essure beyond a predetermined point to rstop themotor and upon decrease in receiver pressure below a predetermined point to start the motor, lfluid pressure voperated unloading means for said and pilot means formipplying pressure to said unloading means to eifect Huid under unloading and for venting the fluid previously Asupplied whenthe compressor attains substantially full' running speed, to load the compressor, said pilot vmeans including a valve opened upon stopping of the motor and ,closed when the motor has attained full run- :ning speed after-,closing of said pressure switch. 1 f In testimony whereof I alix my signature.

FRED nHoLDswoRTH. 

